1. Field of the Invention
This invention relates to a laser positioner for automatically measuring geodetically specified points and optically forming a geodetic pattern on a working face in construction projects, tunneling projects or the like by use of surveying laser instruments, and a method for optically marking boring points on a working face of a tunnel in a tunneling project by use of the laser positioner.
2. Description of the Prior Art
It is a prerequisite to make an elaborate survey and precisely mark on a working face in order to determine the surveying reference points necessary for carrying out various construction projects such as road and tunneling works. Though the surveying was onerous and troublesome in the past, the accuracy of surveying for road, tunneling, and building construction and the like has been significantly improved and the operational efficiency of surveying has been significantly advanced by use of laser surveying instruments. The laser instruments using a visible ray have been advantageously applied to the tunneling projects carried out in dark places.
As one example, the work of marking points at which explosive charging holes are to be bored in a working face of the tunnel cannot be automated even now, and has such work thus far been carried out manually. In the tunneling operation (e.g. New Austrian Tunneling Method: NATM; patented to L. V. Rabcewicz), the hard base rock of the working face is often blasted with explosives. Therefore, the holes for charging the explosives are previously bored in the working face at the geodetically specified points predetermined in accordance with designs of construction which are strictly made in advance. Although the specified points at which the explosive charging holes are bored in the working face of the tunnel can be designed automatically with ease by use of a computer, the work of marking at the design points for boring the explosive charging holes has been manually carried out, and automation of marking on the working face in the tunneling construction cannot yet be accomplished.
It would be possible to utilize a computer and a laser system in marking the points on the working face of the tunnel. That is, the boring points at which explosive charging holes are to be bored in the working face can be predetermined by use of the computer. Then, while directing a laser spot corresponding to one of the predetermined boring points onto the working face by use of a laser oscillator under the control of the computer, the position at which the laser spot representing the predetermined boring point is formed on the working face of the tunnel is manually marked with paint. The manual marking with paint is successively continued for other boring points in order, but turns out to be a very troublesome chore.